Etymology

From Proto-Slavic *dolъ ‎(“dale, valley”), from Proto-Indo-European *dʰal-. Cognate with Old Frisian del, Old Saxon dal, Dutch dal, Old High German tal (German Tal), Old Norse dalr (Swedish dal), Gothic 𐌳𐌰𐌻𐍃 ‎(dals). The Indo-European root is also the source of Ancient Greek θάλαμος ‎(thálamos).